Electron discharge device



Juy 23, 1946. l G. P. cHEvlGNY ELEcTRoN DLSCHARGE DEVICE Filed March 16, 1942 Patented July 23, 4,1946

ELECTRON DISCHARGE DEVICE Georges P. Chevigny, New York, N. Y., assigner to Federal Telephone and Radio Corporation, a

corporation of Delaware Application March 16, 1942, Serial No. 434,914

6 Claims.

Thisinvention relates to electron discharge devices and circuits and more particularly to such apparatus adapted to operate at ultra high frequencies. It has for its object to improve the operating performance, and increase the frequency and the power output at which such devices may be made to operate eifectively. A related object is to provide a simple compact construction, by which an eiiicient-operation is obtained. A further related object is to providean improved form of such' devices which will be readily adaptable for operation -with co-axial line structures. Y f l Y There have heretoforefbeen provided vacuum tubes having resonant cavity type circuits arranged to establish ultra high frequency resonance. `At fthese frequencies, Vin order to avoid large inductances and distributed capacities, the sizeof the electrodes should be 'made small in orderthat a substantial transfer of energy of the ultra high frequency may-be made effective over the electrodev areas. Furthermore, it is desired that the electrical impedance of the elements couplingsthexesonant circuits-with the tube electrodes' should be made small in orderto reduce thezpowerloss acrossth'em. e Y.

In accordance with this invention there is provided a compact symmetrical arrangement of the component 4parts of the tube and cavity circuits, which reduces the effective size ofthe electrodes tohalf their actual size,"and thereby permits a high energy output ata very high frequency. kA featurefisran arrangement'of the cavities symmetrically with respect'to the central section of the electrodesso that the tubevoperates as two tubes,one on' eitherside of the central section. A further ffeatureis the formation offtheelectrodes ,and the tube in such Yamanner that two separate resonant circuitsl maybe provided lbetweeng'rid and -anodeand two further tuning means may be provided betweencathode and grid .eircuits.` In this manner, one tube may be made to do `the work of two and increased power and bhigher operating frequencies may be obtained.

Other objects and further features of novelty and 'invention Willhereinafter be pointedy out or will become apparent to those 'skilled in the art from a readingrr of the "following specification in connection withl the drawing annexed hereto. In said drawing` Fig. 1 depicts a partly sectionalized andvbroken 'away'elevation Vo1? an electron discharge device and its associated circuits in accordance with lfeatures of the invention;

(Cl. Z-27.5)

Fig. 2 is a sectional view taken substantially in the plane 2-2 in Fig. 1; and

Fig. 3 is an alternative embodiment of. a portion of the device shown in Fig. 1. Y Y,

The device shown in the drawing isa simple triode having its output connection so provided that it may be readily connected in av co-axial transmission line. The y arrangement further permits provision of a pair of resonant cavities between the grid and anode and between cathode and grid. y The tube as shown comprises a doublehelix cathode l0 concentrically surrounded by a grid II v.and thenby an 'anode I2. For feeding cathode heating voltage vto cathode I0 symmetrically about the electricalmid-point th'ereof, a rigid lead-in wire I3v is connected `rigidly to one end of cathode I0 (at the right in the drawing). Lead-in I3 thus serves to support that end of the cathode. The other respective ends of the cathode h'elices aresupported by two further rigid lead-,in conductors. I4, I5, and all the cath?.r

ode leadinconductors I3, I4, and`l5 are brought out of the evacuated envelope'of the device through a glass press I6. l

Grid I I comprises ,a plurality o f longitudinally extendingr rods or wires (see r also Fig. 2) rigidly xed at one end to a collar I1 and at the other to a bellows I8, whereby changes in lengthV of th'e grid'due` to heating in operation may bev ab` sorbed by the device without displacing' the grid with respect to cathode I0 and anode I2 so as to impair performance of the device. Inlorder that connection may be made to the grid from both sides of the anode, two annular lead-in members I9, 20 are provided. Members I9 and'Z include longitudinally extending iianges I9' and 20"to aid in sealing them to insulating portions ofthe envelope. At the end of th'e device Wherethe grid is held fixed, collar I'I is )provided with'a radially extending ange 2Ifb'y means of which collar |1` is rigidly xed by bolting va ring 22 and ange 2l tothe annular member' I9.

'As' mentioned vaboveLthe other Vend o f grid II isr connected to annularv member u20 through a bellows I8. 'I'he purpose Yof bellows I8 is to take up with relative ease changes in lengthi of the grid in operation, and it' also serves to provide a highlyv desired, the disposition of4 all elementsofwgrid f I I may be still more securely maintained by providingl spring means 23 within bellows lfwhereby all th'e wires of grid II are constantly under a certain amount f tension.

1 It will be noted that the arrangement thus far described permits provision of an additional leadin 24 for the mid-point of cathode I!! whereby cathode output from a radio frequency point of view may be taken symmetrically from both ends of the tube asis also the case for grid connections. Inasmuch as lead-in I3 supporting the electrical mid-point o-f cathode III may extendr due toh'eating during operation, it is preferable that lead-in 24 include a ilexible (e.- gstranded) portion, whereby no stresses will be set up during Y operation. g Y

Anode I2 has a rather extensive operating sureXtending a substantial distance therealong. In the form shown, anode I2 further includes flanged portions I2 similar to flanges I9' and 20' on the annulargrid lead-ins.. 'I'he evacuatedportion of the discharge device thus comprises press I6,. annular grid lead-in l 9, i insulating` collar p25 sealed to flangesl and I2',1anode I2, afu'rther insulating-collar 25 sealed to flangesI2. and 20', gridlead-inZIl', and a further press 2'I` sealed tothe other ange20, as will be clear,k

`lt will be seenthat I have described a relatively simple structure foruse inv connection with co-` axial transmission lines and resonant circuits of the transmission linetype. f Intheform shown.va

concentric linecomprising three cylinders 28,29.- may be connected Vto oneend of .thetube and ianother concentric line comprising-tubular con;

ductorsr3l, 32 and. 33 maybe connected-to the i other end thereof. Lines 28,-'and3fl areshown directly .connected `to anode I2, lines `29 .and 32 areconnected directly to the grid leads-in 20 and I9 respectively, and linesr30 andk 33 are provided with'end-plates 34 and 35 for symmetrical connection to theelectrical mid-point of cathode I0. By-pass condensers 44, 4 5 are shown linking the outer ends of cathode leads-inrIlI, I with the cathode line 33. y'

`lIf desired, Atuning means may be providedto tunevany of the' grid-anode andV cathode-grid circuits described. In the form shownQone'side of the grid-anode circuitl may betuned with slideable capacitative tuning elements 3B, 3'!l and the other side'witha similar pair 38, 39. ,These l elements'may be jof known form. and slideable longitudinally between lines 28 and VV29,-and 3I and32, as the case may be. Y'These tuning means are'shown as capacitatively ,separated so that high B-supply lvoltages mayY beplaced on the anode without affecting grid potentials, as Ywill be clear. .Y Ii preferred, a relatively fixed capacitativeponnection could be madev between line;28

and'anode I2 and between line 3! `and anode'IZ so that a more rigid singleV conductive tuning ele- VVment could be used instead of elements 3,6, 3;?,

38 and 39. 1 Connections of this latter nature are shown in the copendingapplication Serial No. 431,134.` filed February 14,V 1942 ofrE, Labin and myself. Furthertuning means, which mayzbe similarto that used `in connection with the gridanode circuit, may be provided adjustably to tune the respective lcathode-grid circuits. These further tuningjmeans, designated generally 40,f4|,

' are shown adjustably slideable ,between lines Y29` and 30, and-32 and 33, as the-case. may be.

It will be seen that I have provided an-extremelyguseful form of highfrequency discharge device Wherein'a singletube Ymay be employed effectively .tot deliver -thepower that would beexpected .of

two former devices. Although there is only a 4 single cathode, the eiect of the symmetrical construction of the electrodes and resonant circuits is to cause the half of the apparatus to the right v'designed with relative compactness, a higher op- 10` tively eiiicient disposition of the several resonant circuits gives a maximum of access of outer por- VAtions ofthe anode to cooling media; and in order to increase effectiveness of such cooling, the Vouter 15` face concentrically surrounding the grid IIV and erating frequency may be obtained. The relaperiphery of-anode I2 may be provided with cool- Figr3 illustrates another embodiment of the above-described tube. In this embodiment'a single cylindrical line 41 surrounds anode I2 andis coextensive with grid lines 29r and 32 as lines 28 and 3'I ,were with the same grid lines in Fig.; 1. This arrangement thus provides a single tank extending between both grid leadsV I9 and 20 and anode I 2. Y Coupling capacity between Vthevtank and the anode may be provided by appropriately spacing that partof line V4I adjacent anode I2 therefrom.v High anode potential is supplied 'in a well-known manner (notrshown)v through` a glass bead insulator inthe surface of line 41 and in this way these high potentials are, kept Voff external elements of the'device. If desired., the anode may be cooled by providing longitudinally extendingV slots or other apertures `(also #not shown) in line 41 and a draft rforced therethrough. f

It is to be noted that II have described a completely symmetrical device wherein the half "to one side of a midsection normal to the laxis of the device may function symmetrically and concurrently with the other half. VIn other words the device could,A from y an electrical point of view,V be rconsidered as two "separate Ydevices formed by dividing along themidsectionof the anode. The ability to tune both cathode-grid and grid-anode circuits symmetrically aboutthis midsection permits all circuits to operate at more tail in connection with the preferred form shown,V

it is clear that many modifications, additions and omissions may be madewithin the 4scope Vand spirit thereof as defined in the appended claims. I 1 What is claimed is: l Y

f 1. An ultra high frequency electron discharge device comprising concentrically. mounted cathode, grid and anode electrodes,l the'anodelbeing the .outer of said electrodes, anzevacuated envelope enclosing said cathode,v saidl .gridfand a portion ofp said anode, an annular member of conducting material passing through av portion of said envelope on one side of said'anode,.a`v further annulary member of conducting.. material passing through a portion of said'envelopeon the other side of said anode, lcoth saidpannular members being co-axially disposed with respect to said electrodes and conductively connected with said grid, and cavity resonator means extending across outer portions of said annular' members and outerportions of said anode.

2. An electron discharge device according to claim 1, wherein said cavity resonator means includes a rst cavity resonator connected between said first-mentioned annular member and said anode and a second cavity resonator connected between said further annular member and said anode, said cavity 'resonators being generally symmetrically disposed longitudinally withrespect to each other and also being symmetrical co-axially with said electrodes.

3. An electron discharge device according to claim 1, wherein said grid electrode is directly connected at one end to one of said annular members and wherein flexing means are provided on the other end thereof and connected to the other of said annular members.

4. An electron discharge device according to claim 1, wherein said grid electrode is connected at one end directly to one of said annular members and wherein the other end thereof is connected to the other of saidannular members through a bellows.

5. An electron discharge device comprising a centrally positioned, longitudinally extending cathode, a tubular grid surrounding said cathode, a tubular anode about said grid, means supporting said electrodes, said means including a pair of longitudinally spaced plates, means rigidly attaching one end of said grid to one of said plates and a iiexible bellows forming a continuous conductive connection and a longitudinally extensible support interconnecting the other end of said grid with the other plate, and means forming a sealed envelope about said electrodes.

6. The combination according to claim 5, in combination with a tension spring inside of said bellows attached at one end to the other end of said grid and at its vother end to the other plate to maintain said grid under tension.

GEORGES P. CI-IEVIGNY. 

